Collaborative Research: Frictional and Mineralogical Properties of Sediments Entering Subduction Zones: Controls on Stress State and Earthquakes

科学摘要：这项研究将提供进入南开和哥斯达黎加俯冲系统的天然沉积物摩擦系数的实验室测量。摩擦研究将在0.1-50兆帕的有效围压下进行环剪和直剪试验相结合的方式进行。样品将通过X射线衍射(用于散体和粘土矿物学)、粒度、扫描电子显微镜/能谱分析(SEM/EDS)和湿化学(用于生物硅含量)进行表征。将其力学性能与粘土矿物学进行对比，以确定粘土矿物对摩擦系数的影响。这项研究将评估蒙皂石-伊利石转变和蛋白石-石英反应在控制俯冲带孕震活动上倾极限方面的作用。

Science Summary: This study will provide laboratory measurements of the coefficient of friction of natural sediments entering the subduction systems of Nankai, and Costa Rica. The frictional studies will be conducted in a combination of ring shear and direct shear experiments at effective confined stresses between 0.1-50 Mpa. Samples will be characterized by X-ray diffraction (for bulk and clay mineralogy) grain-size, SEM/EDS geochemistry, and wet chemistry (for biogenic silica content). The mechanical properties will be compared with the clay mineralogy to determine the effect of clay minerals on the coefficient of friction. The study will assess the role of the smectite to illite transition and opal to quartz reactions on controlling the up-dip limit of seismogenic activity in subduction zones.